mdToolbar: inserted div breaks layout and functionality

[Frank3K]

After commit 9b861fd the md-toolbar creates an extra child div. This extra child div creates problems when one has specified (for example) layout or layout-align attributes on the md-toolbar element since these styles now apply to different elements.

Furthermore, @daniel-nagy has left a comment on the original commit explaining problems with ng-include and ng-contoller.

[topherfangio]

This was fixed by #4423 in commit a09b9ab. I transposed the numbers in my commit message.